The proposed research is aimed at providing knowledge concerning the development of self-concept in adolescent males and females. Adolescents in grade 5-12 will be tested with a semantic differential self-concept scale each of the three years of the project. In addition, the motivational components of self-concept will be assessed by examining changes over time in the interest patterns of adolescents and relating these changes to changes in the self-concept. Interest patterns will be assessed through questionnaires administered at the same time as the self-concept. A cross-sequential design will be employed in order to measure these relationships, with a sample of previously untested subjects being added for each grade level each year of the study. Changes in self-concept will be assessed as a function of age, sex and socioeconomic status. Changes in interests will be assessed for these variables as well as being related to school achievement and changes in the factors of the self-concept. These latter data will test the notion that the self-concept has motivational properties vis-a-vis the formation of recreational, vocational, and educational interests.